1. Field of the Invention
The present invention relates to a webbing retractor retracting an occupant restraining webbing therein, adapted for use in a seatbelt system for a vehicle.
2. Description of the Prior Art
In the seatbelt system, the webbing is retracted from one end portion thereof in the webbing retractor and stored therein.
The webbing retractor is provided with a locking mechanism in order to put the occupant in a securely restrained situation by the webbing.
In such locking mechanism it is common that the webbing is automatically locked to prevent it from being unwound after the occupant dons the webbing.
For example, the automatic locking mechanism proposed in U.S. Pat. No. 3,635,420 (Inventor: Romanzi, Jr.) is such constructed that a restraint of the occupant by the webbing and a release thereof from the webbing are detected in accordance with a rotation of a webbing takeup shaft and a pawl engaged with a ratchet wheel fixed to the takeup shaft is controlled by a control plate to be engaged with the ratchet wheel so that the webbing is automatically prevented from being unwound after the occupant wears the webbing.
In such conventional webbing retractors, however, means for detecting rotation of the takeup shaft to control a motion of the pawl is made complicated or such means requires many parts therefor, which results in increase of manufacturing costs.